This is not a complete article yet, but a short note for a comment in ZeroMe :) Maybe later I will write more in detail. The first computer I did with my own hands was Radio 86РК.
I started doing it in late 1990, and launched it in the summer of 1991. I had two memory modules defective, and I didn’t have any oscilloscopes or any other tools ... I even determined the status of the data and address buses using a probe from the LED :) But the problem was detected and soon the computer started working. It had 32kbytes of RAM, a 64x25 text screen and a tape recorder as a program carrier.
I did not have a tape recorder, so after each turn on of the game and other programs I manually entered byte by byte in hexadecimal form :)
When the refrigerator was turned on at home, the computer would hang due to a voltage surge. No capacitor banks saved. So, during operation, the refrigerator had to be turned off :D But with this computer I first learned programming in machine codes. I wrote on a piece of paper a program in assembler 8080 (the Soviet analogue is KR580VM80A), manually translated this program into machine codes, arranged the addresses of transitions and in this form entered the program into the computer's memory.
Although now my Radio 86RK is still somewhere stored by my mother in the village, I have not seen him for a long time and I don’t have his photos. Anything higher is on the Internet. My case was the same as in this photo. Only the keyboard was different, with tight little buttons :)